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Jittery RPM's by Alblindi
Started on: 10-13-2014 04:12 PM
Replies: 4 (82 views)
Last post by: phonedawgz on 10-14-2014 10:21 AM
Alblindi
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Report this Post10-13-2014 04:12 PM Click Here to See the Profile for AlblindiSend a Private Message to AlblindiEdit/Delete MessageReply w/QuoteDirect Link to This Post
After driving the Fiero for a little while following a car show, I noticed it was a little rough going down the road. It would jerk subtly, as if the transmission was wanting to seize up. So initially, I thought the transmission fluid was just getting really low. But I had also noticed that when the car started jittering (assuming when the TCC would kick in), the Tachometer would become sporadic for a moment. When I got home, though, the engine light came on, so I checked it and got the codes 22, 32, and 44. I then recalled that for the car show, I sprayed down the engine compartment, possibly causing a short or a leak in the vacuum system.

Any suggestions?
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Alblindi
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Report this Post10-13-2014 04:24 PM Click Here to See the Profile for AlblindiSend a Private Message to AlblindiEdit/Delete MessageReply w/QuoteDirect Link to This Post
Also forgot to mention that it idles roughly now; it has nearly stalled a few times just sitting there. I'm scared to run it again xD
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Gall757
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Report this Post10-13-2014 06:41 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
Fieros do not like to take a bath.....'sprayed down' means what exactly? The "weather seal" connectors are designed to keep water out, but if water gets in....the weather seal works the other way and keeps the water in!...sometimes you just have to wait for everything to dry out.

[This message has been edited by Gall757 (edited 10-13-2014).]

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sardonyx247
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Report this Post10-14-2014 03:43 AM Click Here to See the Profile for sardonyx247Click Here to visit sardonyx247's HomePageClick Here to Email sardonyx247Send a Private Message to sardonyx247Edit/Delete MessageReply w/QuoteDirect Link to This Post
The prob I used to have washing engine bays (back when I was 16) is water in the distrib cap, pull off the cap, wipe it out good, spray it with WD-40 (Water Displacer #40, actual meaning) and put it back on.
Good place to start, it didn't ever just dry itself out either. Now I keep water away from the electronics in the bay, and start it up right after to help dry it.

Edit to add: it caused the same prob you are having.

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[This message has been edited by sardonyx247 (edited 10-14-2014).]

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phonedawgz
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Report this Post10-14-2014 10:21 AM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
If the tach is wacking out more than just following the actual engine RPMs then look at primary ignition system components. That would be pick up coil, ICM, ICM - Coil low voltage cable, and the Ignition Coil itself.

If the way your tach is wacking out is that it is jumping high, then definitely look at primary ignition components.

A wacking out tach can be caused by the secondary voltage jumping to the primary side of the ignition coil. This is due to broken down insulation between the secondary and the primary. The insulation between the secondary and primary can/will be damaged by high resistance in the secondary. That would be spark plug wires with more than 10K per foot or overly wide spark plug gaps.

So if your spark plugs haven't been changed for a long time you should replace them. That includes the FRONT THREE.
If your spark plug wires are old they could very well have high resistance. You could measure the resistance or just replace them.

Secondary voltage reaching the primary will eventually cause the ICM to fail.

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Again this all assume the tach is wacking out more than just following the actual engine RPMs

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